One area in which the invention finds particular but not limited utility is in the manufacture of concrete pipe for use in drainage and other projects. Such pipes are commonly formed in steel molds disposed in upright positions. That is, each pipe is cast with its axis vertical. After the pipe has "set", the form or jacket is stripped from the pipe and the pipe is placed in a selected are a for curing, usually by means of a kiln, oftentimes heated by steam. It is also common practice to enclose the kiln, preferably by some form of portable or permanent structure in order to eliminate expense, maintenance and use of space that could be employed for other purposes.
Flexible material of any known form is preferred for the portable or temporary canopies but many problems arise in the covering and uncovering of pipe or other articles because the pipe alone is of substantial size, as is the kiln area, and consequently, the canopy becomes also of substantial size and weight and therefore can be heavy and cumbersome to handle. At the same time, it is desired that, when the kiln area is not in use for kiln purposes, it be made easily available for other purposes.
According to the present invention, the aforesaid and other problems are eliminated by the provision of an overhead system that easily and conveniently handles the canopy, moving it quickly between kiln and storage positions with a minimum of apparatus. The system uses pickup means to raise and lower the canopy--which in kiln position somewhat resembles a tent with a flat roof--over the pipe. When the canopy is picked up and stored, auxiliary supports for one end of the canopy may be removed from the floor, leaving the floor open and unobstructed. Means is provided for picking up the canopy at one end as well as in the middle so as to eliminate the sagging of the canopy onto the cured pipe during canopy folding and storage. Storage of the canopy is effected against a wall or similar support so that, although it is out of the way when stored, it is easily available to be lowered again over a new batch of pipe. etc. to be treated.
Further features and advantages will become apparent as a preferred embodiment of the invention is disclosed in detail in the ensuing description and accompanying sheets of drawings, the figures of which will be described immediately below.